1. Field of the Invention
This invention relates to a device for the computerized analysis of human spinal segment mobility which includes an inclinometer disposed within a piezoelectric impulse and sensing head so that the angle of incidence of the apparatus on the spine can be measured as spinal mobility is measured and a process for interpreting the characteristics of a wave form generated from the piezoelectric sensor which is in contact with the spinal segment while an impulse is applied to the segment.
2. Description of Prior Art
A spinal xe2x80x9cmotion segmentxe2x80x9d may be defined as two adjacent vertebrae, the intervertebral disc residing between and connected to the two adjacent vertebral segments, the collateral and capsular connective tissue, proximate musculature, and the fascia and integument, all associated with the motion segment. The sensing and measuring of joint mobility of human spinal segments has been described by many practitioners skilled in the art as manually and subjectively determining spinal segment mobility relative to a written standard as well as adjacent spinal segments. In the early art form, developed by practitioners of physical manipulation of spinal segments, the practitioner would manually stabilize the spinal segments superior and inferior to the segment selected for testing of a patient who was lying on a therapy table or sitting in an erect position. While the adjacent segments were so stabilized, the integument over the spinal segment to be tested would be grasped between the thumb and forefinger of the practitioner so that the spinous process of the segment in question would be trapped within the patient""s integument and between the thumb and forefinger of the practitioner. The practitioner would then attempt to move the segment, using the spinous process as a lever, and at the same time make a mental observation and comparison to a reference determined by a written standard and experience and practice on many subjects. The observations would be graded and recorded by the practitioner. Intensive professional training is required to be able to sense and grade the amount of mobility or xe2x80x9cstiffnessxe2x80x9d of each spinal segment. Grading mobility is an art form and while one practitioner might consistently grade the mobility with a reasonable amount of accuracy and precision, additional practitioners might disagree with the mobility grading of the first practitioner. Therefore, the accuracy of the grading varied with the experience and interpretive skills of individual practitioners.
Several years ago, laboratory devices were constructed so that a subject could be positioned reproducibly on a therapy table and a lever operated transducer would be applied to the spinal segment in question and moved through a given range of motion so that the energy required to move the segment was recorded and correlated to some chosen reference standard. This method was more objective but not practical for routine practice.
In 1992, a device for testing mobility and resistance of a spinal segment was invented. The device was comprised of a piezoelectric sensor that could be positioned in series with a spinal segment where a fixed pressure could be applied through the transducer so that the integument over the segment would be compressed by a known and reproducible amount. When the required compression was achieved, a cylindrical shaped metallic body, would be accelerated to impact the side of the piezoelectric sensor opposite the spinal segment so that a force impulse would be transmitted through the transducer in series with the spinal segment to be tested. An electronic wave form, characteristic of the combined resistance of the components in series, would be elicited upon the impact. Since all of the elements in series with the spinal segment, but not the spinal segment itself, were known or fixed to some standard, the variance of the system wave form would be attributed to the resistance of the spinal segment mobility relative to the adjacent spinal segments. This is the present state of the art and science.
While the present state of the art and science with the application of piezoelectric sensing devices has resulted in significant improvement over prior art, at least one additional variable exists: the angle of incidence of the device against the spinal segment. As the angle of incidence of the device against the spinal segment varies, the captured wave form will also vary to some degree upon impulse formation. The angle of incidence depends on the skill of the practitioner. Therefore, the accuracy of this device will also vary depending on the skill of the practitioner.
Highly skilled practitioners can be accurate in determining the correct angle of incidence but other practitioners may not be able to exactly match or reproduce angles selected by their peers. It is consistent with good laboratory practice that there be a given standard i.e. xe2x80x9cthe gold standardxe2x80x9d that is the most accurate and precise standard available at the time of the present state of the art. Therefore, in the interest of good laboratory practice and in the interest of solving the problem of the potential inaccuracy of test results, the inventors hereof have conceived of a device which removes the greatest portion of the inaccuracies of spinal segment mobility test results.
Piezoelectric percussion testing is commonly used for testing materials with critical stress reliability needs i.e. microcircuits, aircraft frames and structural components, bridge materials etc. There are engineering standards for assessing the information contained in the wave form outputs from piezoelectric sensing systems used for structural materials testing. A search of literature and prior art fails to teach a method for gathering and interpreting the information trapped in a wave form generated as a result of piezoelectric sensing of percussion testing of human spinal segments.
While the present state of the art in spinal segment mobility testing has resulted in an improvement over prior art with the application of piezoelectric sensing devices and the logging of the amplitude of the wave form output from such piezoelectric sensing devices, there is much more complexity in the differing shapes of the wave forms elicited during the mobility testing of human spinal segments. Initial experiments and demonstrations have shown that there is useful information trapped in each wave form output of a piezoelectric sensor interposed in a percussion system for testing human spinal segment mobility. No method of capturing the mathematic representations of the wave form output from the percussive testing of human spinal segments and then manipulating and interpreting such mathematic representations so as to define the amount of segmental resistance or mobility and the condition and characteristics of such segmental resistance or mobility can be found in the prior art.
I provide a device for the measurement of spinal mobility which includes an impulse and sensing head capable of determining spinal segment mobility by applying a force impulse at an angle of incidence to a spinal segment and generating a wave form characteristic of spinal mobility. An inclinometer, disposed within the head, determines the angle of incidence of the head in contact with the spinal segment in at least one, preferably three, axis. Signal generating components are attached to the data acquisition circuitry, the inclinometer, and the head so that a signal corresponding to the angle of incidence of the head at substantially the same time that the head applies an impulse, will be captured by the data acquisition circuitry. Data acquisition circuitry also captures the wave form and a signal characteristic of the force impulse.
The impulse and sensing head includes a probe, a piezoelectric sensor firmly attached to the probe, an anvil firmly attached to the sensor, an electromagnetic coil and an armature. The armature is inserted without attachment into the electromagnetic coil and configured so that when the coil is energized, the armature is accelerated to impact the anvil and thereby produce the force impulse which travels through the piezoelectric sensor and causes the piezoelectric sensor to generate the wave form. A pressure sensor is attached to the head and configured so that when the probe is pressed against the spinal segment and reaches a predetermined pressure, the pressure sensor causes a release of a burst of current that energizes the electromagnetic coil. The pressure sensor is also attached to the signal generating components which output data, characteristic of the pressure of the probe in contact with the spinal segment, to the computer. The device is portable and hand-held.
The data acquisition circuitry includes a computer which has a screen. The angle of incidence in a three axis configuration is displayed on the screen. Information indicating the angle of incidence, the force impulse, the pressure of the probe and the wave form are stored in the computer. This information can be merged together, sorted, and logged for each patient. The computer can recall and print this information.
The device can be configured so that the head will only apply force impulse at a specific angle of incidence or within a specific range of angles of incidence. The device may also be constructed so that a signal, which may be visible or audible, is elicited if the angle of incidence does not fall within a specific range. Alternatively, the wave form may be blocked from data acquisition circuitry if the angle of incidence is not within a specific range.
The device can also be used to treat patients. The probe of the invention may oscillate by repetitively accelerating the armature and impact the anvil at a controlled frequency and a predetermined time period. The device would then be applied to a dysfunctional spinal segment for the purpose of improving joint mobility. Preferably, the frequency may be varied between approximately 4 and 12 hertz in increments of approximately 0.1 hertz.
I also provide a process of measuring spinal mobility which includes generating an impulse of a known force with a percussion source and transmitting the impulse through a piezoelectric sensor into an integument overlaying a spinal segment. This causes the piezoelectric sensor to generate a wave form having characteristics of the mobility of the spinal segment. The waveform is captured in a computer and the characteristics of the wave form are interpreted so as to make a correlation between mobility of the spinal segment and the characteristics of the wave form. The wave form may also be represented graphically on a computer screen or printed. The characteristics of the wave form are mathematic and visual. The graphic representation of the wave form is described statistically and mathematically. Ratios are calculated that mathematically describe the wave form offsets and asymmetries from an expected normal wave form. Ratios of each xc2xc of the half wave form time from zero to peak versus time from peak back to zero and rise time versus fall time are determined and compared with the same ratios of an expected normal wave form. The resonant frequency of each spinal segment tested is calculated as a result of the wave form. A harmonic frequency is calculated of an oscillating percussion that would improve spinal mobility if applied to the spinal segment. The wave form is stored in the computer and displayed on the computer screen. The ratios are also stored in the computer and displayed graphically as numerical representations of the expected normal spinal mobility versus the spinal mobility of the spinal segment being tested. Charts are produced containing the ratios and the charts are used to determine a course of treatment. The results of the course of treatment are tracked against the expected normal spinal mobility. A file history of each patient is compiled which contains the mathematic and graphic representations and the ratio of that patient""s spinal mobility. The mathematic and graphic representations in the ratios are transferred to a computer diskette and may be transferred to another computer.